Shear mechanism



www

'Mwah T1934., J, A. SMATMANS SHEAR MECHANI'SM WNW. OGGOOOmmxmUGOGOOON.Wmmu|-|llm Filed Jan. 50, 1952 Patented Mar.. i3, 1934 SHEAR MECHANISM.lohn A. Smitmans, Pittsburgh, Pa., assigner to United Engineering &Foundry Company, Pittsburgh, Pa., a corporation of PennsylvaniaApplication llanuary 30, 1932, Serial No. 589,889

l5 Claims.

This invention relates to the shearing of elongate stock, such as metalbars, strip and the like, into sections of predetermined lengths as itis delivered from a rolling mill or similar continuously operatingfeeding mechanism and has for its primary object the provision of animproved system of apparatus for accomplishing this end in which acontinuously operated flying shear is utilized and which in addition toproducing regular cuts of predetermined lengths is adapted toautomatically control the length of the rst cut made on each piece ofstock whereby to reduce to a minimum the amount of waste customarilyincurred by cropping cuts or random cutting.

A more particular object is to provide a system of apparatus of thischaracter in which provision is made for automatically controlling theentrance in the shear of the leading end of each piece of stockdelivered at random from a rolling mill or the like and for doing so insuch a way as to determine the amount of material removed by the rst cutwithout interfering with or altering the regular operation of the shearor rolling mill. This as will be readily appreciated is especiallydesirable where it is necessary to use a shear which is so heavy orcumbersome as to render it impractical to start and Stop it or otherwisevary its speed to control the amount of material removed from a piecepfstock by the first cut.

In addition to the aforementioned the invention has various otherobjects all of which as well as its various other novel features andadvantages will be clearly apparent when the following detaileddescription is read in conjunction with the accompanying drawing ofwhich Fig. l is a plan View of a single embodiment of the invention;Fig. 2 a schematic wiring diagram of a control system therefor; and Fig.3 an elevational View of the speed changing differential unit andsynchronizing switch utilized in the system.

Referring to the drawing the numeral 1 designates a flying shear whichin accordance with the invention may be any of a number of well knownforms of shear, but shown as a rotary type comprising a pair of carriers2 and 3 equipped with cooperating blades 4 and 5 which are arranged tooperate upon pieces of stock such as the piece 6 as it is deliveredthereto over a feed roll table '7 by a rolling mill 8. This is a typicalform of set-up commonly employed in steel mills for cutting elongateblanks intosections of predetermined lengths as they are delivered fromthe rolling mill and by means of which the est (ci. 164-68) t i lengthsof the cuts are determined by the relation which the speed of the shearbears to the speed of the blanks.

Ordinarily the shear is driven continuously by a suitable motor, such asmotor 9, at a speed which is regulated by any suitable means inaccordance with the speed of the mill from which the stock to be shearedis delivered. Thus the shear is adapted to produce cuts at regularintervals and the length of the cuts is determined by the amount ofmaterial passing through the shear during such intervals. A difcultycommonly present in such systems is that the stock is usually deliveredfrom the mill at random and as no control is customarily exercised overthe first cuts, considerable Waste is incurred, since under suchconditions the first cuts Vary in length all the way from nothing up tothe regular lengths of the cuts.

To eliminate this diiliculty in accordance with this invention a pair ofpinch rolls 11 are arranged to engage the stock4 at a suitable pointbetween the rolling mill and the shear and are so operated as to controlthe entrance of the leading end of the stock in the shear in such a wayas to get it instep with the" cutting blades and in that way determinethe amount of material removed from the front end of each piece of stockby the first cut. For operating rolls 11 they are coupled by a shaft 12,a differential gear unit 13 and a shaft 14 to a driving motor 15.

For normal operation, motor 15 is adapted to drive rolls 11 at aperipheral speed which imparts to the stock the linear speed required togive the length of cuts desired. Toward this end it may be controlled inany suitable fashion, but to insure this, as illustrated here, asynchronous motor is employed and this is connected by conductors 16 and17 to receive its operating power from a synchronous generator 18 whichis coupled to and driven by shear motor 9, hence providing positivesynchronous operation of the shear and pinch rolls when the latter aredriven by motor 15 alone.

In order that rolls 11 may be utilized to control the entrance of thefront end of each piece of stock in the shears and thereby control thelength of the iirst cut the diiferential gear unit 13 is ernployed. Toutilize it is such capacity its planetary section 19 is mounted in aworm gear 21 and this in turn meshed with a worm 22 mounted on a shaft23 that is connected to amotor 24. Consequently by operating this lattermotor the planetary section 19 of gear unit 13 may be driven and thespeed of shaft 12 and rolls 11 thereby ill altered without varying thespeed of motor 1.5. Obviously by driving motor 24 in alternatedirections the speed of strip 6 may be either increased or decreasedabove or below its normal speed and in that way the frontend of eachpiece of stock may be got in step with the cutting blades of the shearto control the length of the first.

cut Without altering the speed or regular operation of the shear.

As shown here the strip is fed to the pinch rolls 11 directly from theworking rolls of mill 8 and accordingly the pinch rolls arel normallyrun at the same peripheral speed as the mill, and as a result it isimpossible to increase the speed of the strip by increasing the speed ofrolls 11, hence motor 24 is adapted in this set up for operation in onedirection only and that to slow up the stock to get its front end instep with the cutting blades. The slowing up of the stock by rolls 11will of course result in the formation of a loop between the pinch rollsand the rolling mill as shown by the dotted lines in Fig. 2, but withthe proper spacing of the pinch rolls from the mill this involves nodifficulty.

In order to control the operation of motor 24 so that it willautomatically vary the operation of rolls 11 in such a way as to get theleading end of each piece 0f stock in step with the cut'- ting blades 4and 5 it is connected in a circuit 25 extended from a suitable source ofcurrent supply 28 and 29 through a bridging member 27D on a magneticcontactor 27,' and the following control is provided for controlling theoperation of contactor 27.

For initiating the operation of the control circuit used with motor 24 aflag switch 30 is arranged in the path of the stock on the delivery sideof rolls 11 and by any suitable means is adapted for adjustment towardsor away from these rolls to provide the proper starting ofthe motor 24under different conditions of operation such as results from variationsin the speed of the stock as will presently appear. While various formsof switches of this character may be employed the one illustrated isshown as comprising a pivoted lever 31 disposed to be engaged by thestock as it passes thereover. On the lower end of this lever 31 there ismounted a bridge member 32 which is adapted to normally rest in aninoperative position below a pair of contacts 32a and.- 32D when theswitch is not engaged by the stock and to be moved to and held in asimilar position above such contacts when the stock engages the lever`and to complete a current-conducting circuit between such contacts foran instant only when it is being moved upwardly therebetween. Suchbridge is also adapted to complete no circuit through these contactswhen it is permitted to fall to its lower inoperative position by thestock passing out of engagement with the lever 31. are deemedunnecessary inasmuch as such switches are so well known in th'e art.

As shown the contacts 32a and 32h of flag switch 30 are connected in acircuit tfaced from supply conductor 28 by way of a conductor 33 throughthe actuating coil 34a of a magnetic contactor 34, contacts 32a and 32h,a bridging member 35a on a limit switch 35 to supply conductor 29. Henceif bridging member 35a of switch 35 is closed, as it normally is as willpresently appear, when the end of a piece of stock hits flag 30, theactuating coil 34a of contactor 34 is energized and that contactorclosed. This latter contactor is employed for setting in motion themeans Further details of this switch employed for measuring the distancethe rolls 11 must be retarded or turned backward in order to place theend of the strip in step with the shear blades.

While such stock measuring means may take other form, in this embodimentof the invention a ying or synchronizing switch 36 is employed for suchpurpose. Referring more particularly to Figs. 1 and 3 switch 36comprises a rotary brush element 37 which is mounted on a shaft 38iand acooperating ring element 39 on which the brush rides which is secured toa worm gear 41 that in turn is loosely mounted on shaft 38 and meshedwith a worm 42 secured to an extension 43 of shaft 23 to which motor 24is connected. Accordingly ring element 39 is driven by motor 24 wheneverthe latter is actuated and the distance it is turned is proportionate tothe amount of turning imparted to rolls 11 by such motor. lShaft 38 inturn is connected through a magnetic clutch 44 to a synchronous motor 45which like motor 15 is connected to conductors 16 and 17. Hence thedriving element of clutch 44 is driven in synchronism with shear l andhence with the normal speed of the stock. Ob"` -viously the same resultwould be obtained by connecting the driving element of clutch 44 toinotor 15.

To utilize switch 36 for controlling motor 24 to get the leading end ofthe stock in step with the cutting blades of the shear a piece ofinsulating material 46 is mounted in ring 39 to break the circuitbetween it and brush 37 when the latter engages the insulating materialand a' pair of brushes 47 and 48 respectively are arranged to ride onthe hub 49 of brush 37 which is secured to shaft 38 but suitablyinsulated therefrom and on the periphery of ring 39. These brushes 47and 48 as shown in Fig. 2 are connected in a circuit 51 traced fromsupply conductor 28 through brushes 47 and 48, the actuating coil 27a,of magnetic contactor 27 and a normally open interlock 35h on flagswitch 35 to supply conductor 29.

For operating clutch 44 it is connected in a circuit 52 traced fromsupply conductor 28 through a bridging member 34h on magnetic contactor34, and the actuating coil of the clutch (not shown) to supply conductor29. Consequently when flag 30 is operated and contactor 34 closed clutch44 is energized and starts shaft 38 to rotate in synchronism with rolls11 and shear l. With the closing of bridge 32 and the completion of thecircuit through contacts 32a and 32h a holding circuit is establishedfor coil 34a which is traced from contact 32a through a sec ond bridgingmember 34o on contactor 34 to contact B2b. Hence clutch 44 remainsenergized until limit switch 35 is operated to open bridge 35a.

This latter switch 35 as shown comprises bridging elements 35a and 35Dwhich are connected to a pvoted lever 35 that in turn is arranged torest at one end on a cam 53 coupled to the lower drum 3 of shear 1. Onthis cani there is provided a raised portion 54 which is adapted to liftthe outer end of lever 35 when engaged thereby and open bridge 35a andclose bridge 35h and accomplishes this once with each rotation of drum3. As referred to above bridge 35a in opening breaks circuit 33 anddeenergizes clutch 44 to thereby stop shaft 38. At the same time theclosing of bridge 35h completes circuit 51 which causes contactor 27 toclose and it in turn energizes circuit 25 starting motor 24. Theselatter circuits once energized are both maintained energized, until theinsulating block 46 on ring 39 of switch 36 is moved into engagementwith brush 48, by a holding circuit 55 traced about bridge 35h of switch35 through a bridge 27e on switch 27 this being necessary inasmuch asswitch 35 only closes bridge 35h for an instant.

The operation of the invention is as follows; with mill 8 operating at acertain speed motor 9 is adjusted to operate shear 1 at the speedregured to give the length of cuts desired. Switch 30 is then positionedwith respect to shear 1 so as to determine the length of the first cutand to also insure switch 36 and motor 24 having adequate time to makethe necessary corrections to the advancement of the front end of thestock to get it in step with blades 4 and 5 before it reaches the shear,so that after the first cut the lengths of cuts will be uniform. Inother words switch 30 must be timed to be so operated with respect toswitch 35 as to determine the length of the first cut and at the sametime spaced suiiiciently distant from the shear to afford motor 24adequate time after switch 30 is operated by the stock to make itscorrection and be out of service before the stock reaches the shear.

With these adjustments made, when the front end of a piece of stockstrikes flag 30 it causes circuit 33 to be energized, whereupon throughthe closing of contactor 34 clutch 44 is energized. This starts andcauses shaft 38 and brush 37 to rotate in synchronism with the stripuntil stopped by the opening of bridge 35a'I on limit switch 35 which isoperated by cam 53. Thus as cam 53 has a denite setting with respect tothe position of the cutting blades on shear 1, brush 37 of switch 36 iscaused to travel a distance .from its starting point which isproportionate to the distance which the end of the stock travels pastflag 30 before switch 35 operates, or in other words a distance which isproportionate to the length the first cut would have in excess of thatdesired if the stock were permitted to enter the shear at its regularspeed and as will presently appear brush 37 starts each time the switchis operated from engagement with the insulating section 46 of ring 39.

With the opening of bridge 35a on switch 35 bridge 352) is closed. Thusas soon as clutch 44 is deenergized circuit 51 is completed. With thecompletion of this circuit the bridging members 27hl and are closed, andthe circuit 25 energized, the latter bridging' members completingcircuit 55 which holds the contactor closed until vdeenergized by theoperation of switch 36. When circuit 25 is completed motor 24 is set inmotion and. in a direction to retard the speed of pinch rolls 11. Withthe starting of motor 24 the planetary section 19 of gear unit 13 is asstated -moved in a direction to retard the-speed of the motor 24 isdetermined by the distance brush 37 is displaced from vthe insulation46. Hence the angular distance which motor 24 causes shaft 12 and rolls11 to `be displaced less than they normally are is determined by thedistance brush 37 is angularly displaced from the insulation 46. This isbrought about by the motor` 24 being stopped as soon as theinsulation 46is moved by worm gear 41 into contact with brush 37 which breaks circuit51. This occurs when the end of the stock is brought in step with thecutting blades of the shear for the rst cut.

In simpler terms by the aforementioned system motor 24 is so regulatedby switches 30, 35, and 36 that it is adapted to cause rolls l1 torotate a peripheral distance less than normal when motor 24 is operatedwhich is equal to the distance which the stock must be retarded after itleaves the pinch rolls and before it enters the shear to bring the stockinto the shear at the proper time to give the proper length of first cutdesired.

With the switch 30 actuated by the strip to a circuit open position solong as it is `in contact therewith circuit 33 cannot be reenergizedafter contactor 34 falls open until switch 30 is released andreenergized. Hence such circuit is established only once with thepassage through the system of each piece of stock and each time it isinterrupted brush 37 of switch 36 is in engagement with the insulatingblock 46 and in readiness for the next step.

To insure that all cuts after the rst one be of regular length it isnecessary that the stock be traveling at its regular speed when thefirst and all succeeding cuts are made. To accomplish this as statedabove switch 30 is spaced sufciently from the shear to allow the controlsystem and motor 24 to have adequate time to perform their duties and beout of service before the first cut is made. Obviously this spacing maybe altered in accordance with the speed of motor 24.

According to the provisions of the Patent Statutes, I have explained theprinciple and mode of practicing my invention and have described what Inow consider to represent its best embodiment. However, I desire to haveit understood that, within the scope of the appended claims, theinvention may be practiced otherwise than as specifically illustratedand described.

I claim:

i l. In combination with a continuously operated flying shear, means forfeeding stock thereto, a pair of pinch rolls arranged between said shearand said feeding means to engage the stock and normally operatedcontinuously in synchronism with said shear and means under the jointcontrol of the stock and shear for Varying the operation of said pinchrolls between the time they engage the stock and the stock is engaged bythe shear to control the length ofthe first cut.

2. In combination a continuously operated ying shear, means for feedingstock into the shear, a pair of pinch rolls arranged between said shearand feeding means to engage the stock, means for normally driving thepinch rolls in synchronism with the shear, means for varying the speedof the pinch rolls and the entrance of the stock in the shear, and meanscontrolled jointly by the front end of the stock and the shear forcontrolling the operation of said speed varying means to therebyselectively determine the length of the first cut.

3..In combination with a ying shear, a pair of pinch rolls for feedingstock to the shear, means for normally driving said pinch rolls insynchronism with the shear, and means set in motion by the leading endof a piece of stock fed at random to the shear by the feeding means formeasuring the extent to which such end of the stock is out of step withthe shear, means for varying the speed of said pinch rolls to controlthe entrance of the leading end of the stock in the shear and meanscontrolled by the shear of deenergizing said speed-varying means fordetermining the length of the first cut.

4. In combination with a continuously operated flying shear, means forfeeding stock to theA means in timed relation with the cutting operationof the shear.

5. In combination with a continuously operated flying shear, means forfeeding stock to the shear, means for normally driving the feeding meansin synchronism with the shear, means interposed between said drivingmeans and' said feeding means for varying the speed of the feedingmeans, a motor for operating said speed varying means, and means jointlyresponsive .to said shear and the front end of the stock for socontrolling the operation of said motor as to selectively determine thelength of the rst cut.

6. For use in combination with a rolling mill, a continuously operatedflying shear arranged to operate upon the stock delivered from said millto cut it into sections of predetermined lengths, and means arrangedbetween said shear and mill for automatically controlling the entrancein the shear of the front end of said piece of stock delivered from themill to the shear.

`the production of a rst c-ut of predetermined length and then feedingit yata to the' shear.

8. In `combination acontinuously operated flying shear, means fordelivering stock to said constant speed lshear, means for normallydriving said stock delivering means in synchronism with said shear tocontrol the lengths of the cuts produced by the shear, and meansresponsive to the stock and shear for measuring the length the rst cutwould have if the stock is fed at random from the lfeeding means intothe shear, and means controlled jointly by-said shear and said measuringmeans for retarding sald'feeding means sufllciently to get the leadingend of the stock in step with the shear before it reaches the shear tocontrol the length of the first cut.'

9. For use in combination with a rolling mill, a continuously operatedflying shear for cutting va piece of stock into sections ofpredetermined operation of said speed varying means to thereby exercisesuch a control over the entrance' of the stock in the shear as toproduce a rst cut of predetermined length.

10. In combination wltha flying shear, feeding means for deliveringblanks of stock to the shear, a synchronous motor coupled through adifferential gear unit to said. feeding means, a

motor for driving said shear, a synchronous generator coupled to bedriven by said shear motor and electrically connected to saidsynchronous motor, means coupled to said differential gear unit forvarying the speed of said feeding mechanism withoutthe speed of saidsynchronous motor being altered, and means responsive to said .'shearand the stock delivered thereto for controlling the operation of saidspeed varying means.

11. In combination with acontinuously operated flying shear, a pair ofpinch rolls for delivering stock to said shear, means for driving saidpinch rolls in synchronism with said shear, a differential gear unitinterposed between said pinch roll drivingmeans and the pinch rolls,means for operating said gear unit to vary the speed of the pinch rollswithout varying the speed of said driving means, means jointlyresponsive to the strip and shear for measuring what the length whichthe ilrst cut would be if fed at random' intov the shear and meanscontrolled by said meas'- uring means for controlling the operationofsaid gear unit speed varying means to determine the length of the `firstcut.

12. In combination a continuously operated flying shear, a pair of pinchrolls for feeding stock to said shear, means connecting said pinch rollsto a driving motor through a differential gear unit, driving meanscoupled to said gear unit for varying the speed of said pinch rollswithout the speed of said pinch roll driving motor being altered, a flagswitch arranged between said pinch rolls and said shear to be engaged`by a piece ,of stock when passed thereover, stock measuring means setin motion by said flag switch and driven in synchronism'with the normalspeed of said p .nch rolls, a limit switch operated by said shear indefinite relation with its cutting period, means responsive to saidlimit switch for stopping said stock measuring means whereby measuringthe amount of stock traveling past said flag between the time it isoperated and said limit switch is operated, means also set in motionwith said limit switch for setting said gear unit speed varying means inoperation, and means cooperating with said stock measuring meansoperated by said speed varying means for stopping said speed varyingmeans.

13. In combination a flying shear comprising a pair of cooperatingblades mounted on a pair of rotatable carriers, meansfor driving saidcarriers cont'nuously, a pair of pinch rolls for delivering stock tosaid shear, means for driving said pinch rolls in synchronism with saidshear,

"a switch arra'ged between said shear and said pinch rolls to beoperated by the passage thereover of a piece of stock, means set inmotion by said ag when operated which is adapted to measure the amountof stock passing the vflag while said means is in motion, a limit switcharranged to be operated by said shear, means responsive to said limitswitch for rendering said stock measuring means inoperative, other meansset in motion by said limit switch 'for retarding the forward deliverymotion of said pinch rolls, and means cooperating with said stockmeasuring means for rendering said roll retarding means inoperative whenthe amount of material delivered by the rolls has been decreased anamount less than that normally delivered which is equal to the length ofmaterial passing said ilag while said stock measuring means is inoperation.

14. In combination a flying shear equipped with cutting blades, a motorfor driving` said shear, a pair of pinch rolls for delivering stock tosaid los shear, a synchronous motor for driving said pinch rolls, asynchronous generator mechanically coupled to be driven by said shearmotor and electrically connected to said synchronous motor to providefor driving said pinch rolls in synchronism with said shear, adifferential gear unit comprising sun gears and planetary gearsinterposed between said synchronous motor and said pinch rolls, a wormgear supporting said planetary gears, a motor connected by a worm tosaid Worm gear for varying the operation of said pinch rolls withrespect to said synchronous motor, a flag switch arranged between saidpinch rolls and said shear to be operated by the stock delivered by thepinch rolls, a magnetic clutch arrange to be energized by said agswitch, a second synchronous motor connected to said synchronousgenerator operably coupled(to the driving element of said c1utch,anelectrical control element coupled to the driven element of said clutch,a limit switch mounted for operation by said shear adapted to deenergizesaid clutch and stop the control ele-1 ment operated thereby when it isactuated, other means operated by said limit switch for starting saidgear operating motor, and means operated thereby arranged to cooperatewith said control element for stopping said gear motor.

15. In combination, a flying shear equipped with cooperating blades,means for driving said shear at a uniform speed, means spaced from theshear for feeding stock into it, means for varying the speed of saidstock-feeding means, means connected to be driven in timed relationvwith said shear for controlling the operation of said speedvaryingmeans, means operated by the stock for setting said means forcontrolling said speedvarying means in operation, means operated by theshear for stopping said control means, and means operated by saidspeed-varying means for stopping itself.

JOHN A. SMITMANS.

